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conn_impl.go
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conn_impl.go
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package enproxy
import (
"bufio"
"fmt"
"io"
"net"
"net/http"
"net/http/httputil"
"github.com/getlantern/idletiming"
"github.com/pborman/uuid"
)
// Dial creates a Conn, opens a connection to the proxy and starts processing
// writes and reads on the Conn.
//
// addr: the host:port of the destination server that we're trying to reach
//
// config: configuration for this Conn
func Dial(addr string, config *Config) (net.Conn, error) {
c := &conn{
id: uuid.NewRandom().String(),
addr: addr,
config: config,
}
c.initDefaults()
c.makeChannels()
c.initRequestStrategy()
// Dial proxy
proxyConn, err := c.dialProxy()
if err != nil {
return nil, fmt.Errorf("Unable to dial proxy to %s: %s", addr, err)
}
go c.processWrites()
go c.processReads()
go c.processRequests(proxyConn)
increment(&open)
return idletiming.Conn(c, c.config.IdleTimeout, func() {
log.Debugf("Proxy connection to %s via %s idle for %v, closing", addr, proxyConn.conn.RemoteAddr(), c.config.IdleTimeout)
if err := c.Close(); err != nil {
log.Debugf("Unable to close connection: %v", err)
}
// Close the initial proxyConn just in case
if err := proxyConn.conn.Close(); err != nil {
log.Debugf("Unable to close proxy connection: %v", err)
}
}), nil
}
func (c *conn) initDefaults() {
if c.config.FlushTimeout == 0 {
c.config.FlushTimeout = defaultWriteFlushTimeout
}
if c.config.IdleTimeout == 0 {
c.config.IdleTimeout = defaultIdleTimeoutClient
}
}
func (c *conn) makeChannels() {
// All channels are buffered to prevent deadlocks
c.initialResponseCh = make(chan hostWithResponse, 1)
c.writeRequestsCh = make(chan []byte, 1)
c.writeResponsesCh = make(chan rwResponse, 1)
c.readRequestsCh = make(chan []byte, 1)
c.readResponsesCh = make(chan rwResponse, 1)
c.requestOutCh = make(chan *request, 1)
c.requestFinishedCh = make(chan error, 1)
// Buffered to depth 2 because we report async errors to the reading and
// writing goroutines.
c.asyncErrCh = make(chan error, 2)
// Buffered so that even if conn.Close() hasn't been called, we can report
// finished.
c.doneWritingCh = make(chan bool, 1)
c.doneReadingCh = make(chan bool, 1)
c.doneRequestingCh = make(chan bool, 1)
}
func (c *conn) initRequestStrategy() {
if c.config.BufferRequests {
c.rs = &bufferingRequestStrategy{
c: c,
}
} else {
c.rs = &streamingRequestStrategy{
c: c,
}
}
}
func (c *conn) dialProxy() (*connInfo, error) {
conn, err := c.config.DialProxy(c.addr)
if err != nil {
msg := fmt.Errorf("Unable to dial proxy to %s: %s", c.addr, err)
log.Debug(msg)
return nil, msg
}
proxyConn := &connInfo{
bufReader: bufio.NewReader(conn),
}
proxyConn.conn = idletiming.Conn(conn, c.config.IdleTimeout, func() {
// When the underlying connection times out, mark the connInfo closed
proxyConn.closedMutex.Lock()
defer proxyConn.closedMutex.Unlock()
proxyConn.closed = true
})
return proxyConn, nil
}
func (c *conn) redialProxyIfNecessary(proxyConn *connInfo) (*connInfo, error) {
proxyConn.closedMutex.Lock()
defer proxyConn.closedMutex.Unlock()
if proxyConn.closed || proxyConn.conn.TimesOutIn() < oneSecond {
if err := proxyConn.conn.Close(); err != nil {
log.Debugf("Unable to close proxy connection: %v", err)
}
return c.dialProxy()
} else {
return proxyConn, nil
}
}
func (c *conn) doRequest(proxyConn *connInfo, host string, op string, request *request) (resp *http.Response, err error) {
var body io.Reader
if request != nil {
body = request.body
}
path := c.id + "/" + c.addr + "/" + op
req, err := c.config.NewRequest(host, path, "POST", body)
if err != nil {
err = fmt.Errorf("Unable to construct request to %s via proxy %s: %s", c.addr, host, err)
return
}
//req.Header.Set(X_ENPROXY_OP, op)
// Always send our connection id
//req.Header.Set(X_ENPROXY_ID, c.id)
// Always send the address that we're trying to reach
//req.Header.Set(X_ENPROXY_DEST_ADDR, c.addr)
req.Header.Set("Content-type", "application/octet-stream")
if request != nil && request.length > 0 {
// Force identity encoding to appeas CDNs like Fastly that can't
// handle chunked encoding on requests
req.TransferEncoding = []string{"identity"}
req.ContentLength = int64(request.length)
} else {
req.ContentLength = 0
}
err = req.Write(proxyConn.conn)
if err != nil {
err = fmt.Errorf("Error sending request to %s via proxy %s: %s", c.addr, host, err)
return
}
resp, err = http.ReadResponse(proxyConn.bufReader, req)
if err != nil {
err = fmt.Errorf("Error reading response from proxy: %s", err)
return
}
// Check response status
responseOK := resp.StatusCode >= 200 && resp.StatusCode < 300
if !responseOK {
// This means we're getting something other than an OK response from the fronting provider
// itself, which is odd. Try to log the entire response for easier debugging.
full, er := httputil.DumpResponse(resp, true)
if er == nil {
err = fmt.Errorf("Bad response status for read from fronting provider: %s", string(full))
} else {
log.Errorf("Could not dump response: %v", er)
err = fmt.Errorf("Bad response status for read from fronting provider: %s", resp.Status)
}
if err := resp.Body.Close(); err != nil {
log.Debugf("Unable to close response body: %v", err)
}
resp = nil
} else {
log.Debugf("Got OK from fronting provider")
}
return
}
type closer struct {
io.Reader
}
func (r *closer) Close() error {
return nil
}